The PowerToys are split into DLLs for each PowerToy module (modules folder), and an executable (runner folder) that loads and manages those DLLs.
The settings window is a separate executable, contained in editor folder. In utilizes a WebView to display a HTML-based settings window (contained in settings-web folder).
The common contains code for a static libary with helper functions, used by both the runner and the PowerToys modules.